PUBLIC SERVICE CO OF COLORADO Contracts & Agreements

Supplemental Indenture dated as of March 1, 2023, between Public Service Company of Colorado and U.S. Bank Trust Company, National Association, as successor Trustee, creating $850... (Filed With SEC on April 3, 2023)

Supplemental Indenture dated as of May 1, 2022, between Public Service Company of Colorado and U.S. Bank Trust Company, National Association, as successor Trustee, creating $300... (Filed With SEC on May 17, 2022)

Supplemental Indenture dated as of February 1, 2021, between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $750 million... (Filed With SEC on March 1, 2021)

Supplemental Indenture dated as of May 1, 2020, between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $375 million... (Filed With SEC on May 15, 2020)

Supplemental Indenture dated as of August 1, 2019, between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $550 million... (Filed With SEC on August 13, 2019)

Supplemental Indenture dated as of March 1, 2019, between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $400 million... (Filed With SEC on March 13, 2019)

Supplemental Indenture dated as of June 1, 2018, between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $350 million... (Filed With SEC on June 21, 2018)

Supplemental Indenture dated as of June 1, 2017 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $400,000,000... (Filed With SEC on June 19, 2017)

Supplemental Indenture dated as of June 1, 2016 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $250,000,000... (Filed With SEC on June 13, 2016)

Supplemental Indenture dated as of May 1, 2015 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $250,000,000 principal... (Filed With SEC on May 12, 2015)

Supplemental Indenture dated as of March 1, 2014 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $300,000,000... (Filed With SEC on March 10, 2014)

Supplemental Indenture dated as of March 1, 2013 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $250,000,000... (Filed With SEC on March 26, 2013)

Supplemental Indenture dated as of September 1, 2012 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $300,000,000... (Filed With SEC on September 11, 2012)

Supplemental Indenture dated as of August 1, 2011 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $250,000,000... (Filed With SEC on August 9, 2011)

Supplemental Indenture dated as of November 1, 2010 between Public Service Company of Colorado and U.S. Bank National Association, as successor Trustee, creating $400,000,000... (Filed With SEC on November 16, 2010)

Acceptance, Assignment and Assumption Agreement, dated November 8, 2010, by and among PSCo, U.S. Bank Trust National Association and U.S. Bank National Association (Filed With SEC on November 8, 2010)

PUBLICSERVICE COMPANY OF COLORADO (a Coloradocorporation) UNDERWRITINGAGREEMENT $400,000,000 5.125% First Mortgage Bonds, Series No. 20 due2019 (Filed With SEC on June 4, 2009)

PUBLIC SERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee SupplementalIndenture No. 19 Datedas of May 1, 2009 Supplementalto the Indenture datedas of... (Filed With SEC on June 4, 2009)

PUBLICSERVICE COMPANY OF COLORADO (a Coloradocorporation) UNDERWRITINGAGREEMENT 300,000,0005.80% First Mortgage Bonds, Series No. 18 due 2018 300,000,0006.50% First Mortgage... (Filed With SEC on August 12, 2008)

PUBLIC SERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONAL ASSOCIATION, as Trustee SupplementalIndenture No. 18 Datedas of August 1, 2008 Supplementalto the Indenture datedas... (Filed With SEC on August 12, 2008)

[Letterhead of Fredrikson & Byron, P.A]. (Filed With SEC on October 29, 2007)

$350,000,000 Public Service Company ofColorado 6.25%First Mortgage Bonds, Series No. 17 due 2037 UnderwritingAgreement (Filed With SEC on August 14, 2007)

PUBLICSERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONALASSOCIATION, asTrustee Supplemental Indenture No.17 Dated as of August1, 2007 Supplementalto the Indenture dated as of... (Filed With SEC on August 14, 2007)

FINANCINGAGREEMENT between ADAMSCOUNTY, COLORADO and PUBLICSERVICE COMPANY OF COLORADO Dated as of August 1, 2005 relating to $129,500,000 AdamsCounty, Colorado PollutionControl... (Filed With SEC on August 24, 2005)

PUBLIC SERVICE COMPANY OF COLORADO TO U.S. BANK TRUST NATIONALASSOCIATION, asTrustee Supplemental Indenture No. 16 Dated as of August 1, 2005 Supplemental to the Indenture dated... (Filed With SEC on August 24, 2005)

SUPPLEMENTALINDENTURE (Dated asof August 1, 2005) PUBLICSERVICE COMPANY OF COLORADO TO U.S. BANKTRUST NATIONAL ASSOCIATION, (Filed With SEC on August 24, 2005)

EX-1.01 Underwriting Agreement (Filed With SEC on September 4, 2003)

EX-4.01 Supplemental Indenture (Filed With SEC on September 4, 2003)

EX-4.02 Supplemental Indenture No. 15 (Filed With SEC on September 4, 2003)

EX-4.1 Registration Rights Agreement (Filed With SEC on June 11, 2003)

EX-4.4 Supplemental Indenture (Filed With SEC on June 11, 2003)

EX-4.5 Form of Supplemental Indenture (Filed With SEC on June 11, 2003)

EX-4.9 Supplemental Indenture No. 14 (Filed With SEC on June 11, 2003)

EX-4.10 Form of Supplemental Indenture (Filed With SEC on June 11, 2003)

EX-4.1 Registration Rights Agreement (Filed With SEC on December 17, 2002)

EX-4.4 Form of Supplemental Indenture - Mortgage (Filed With SEC on December 17, 2002)

EX-4.8 Form of Supplemental Indenture - Trust (Filed With SEC on December 17, 2002)

EX-4.01 Supplemental Indenture-September 1, 2002 (Filed With SEC on September 27, 2002)

EX-4.02 Supplemental Indenture-September 18, 2002 (Filed With SEC on September 27, 2002)